Air pollution effects on myocardial infarction

OBJECTIVE: Myocardial infarction is an acute and severe cardiovascular disease that generally leads to patient admissions to intensive care units and few cases are initially admitted to infirmaries. The objective of the study was to assess whether estimates of air pollution effects on myocardial infarction morbidity are modified by the source of health information. METHODS: The study was carried out in hospitals of the Brazilian Health System in the city of São Paulo, Southern Brazil. A time series study (1998-1999) was performed using two outcomes: infarction admissions to infirmaries and to intensive care units, both for people older than 64 years of age. Generalized linear models controlling for seasonality (long and short-term trends) and weather were used. The eight-day cumulative effects of air pollutants were assessed using third degree polynomial distributed lag models. RESULTS: Almost 70% of daily hospital admissions due to myocardial infarction were to infirmaries. Despite that, the effects of air pollutants on infarction were higher for intensive care units admissions. All pollutants were positively associated with the study outcomes but SO2 presented the strongest statistically significant association. An interquartile range increase on SO2 concentration was associated with increases of 13% (95% CI: 6-19) and 8% (95% CI: 2-13) of intensive care units and infirmary infarction admissions, respectively. CONCLUSIONS: It may be assumed there is a misclassification of myocardial infarction admissions to infirmaries leading to overestimation. Also, despite the absolute number of events, admissions to intensive care units data provides a more adequate estimate of the magnitude of air pollution effects on infarction admissions.

Acute myocardial infarction in chronic Chagas' cardiomyopathy: report of two cases with no obstructive coronary artery lesions

This report describes two patients with chronic Chagas' Heart Disease who developed clinical and laboratorial signs of myocardial infarction. Both patients presented sudden oppressive chest pain, without precipitating factor. In the first case, the highest MB-CK value was 65 IU, 22 hours after the beginning of the pain. On the second case, it was 77 IU at 18 hours after the beginning of the pain. In both cases ECG changes suggesting non-transmural infarction were present. The 99mTc PYP myocardial scintigram of the first case was positive. Coronary angiograms performed on the 18th and 9th day, respectively, after the acute infarction did not display obstructive lesions. Possible mechanisms causing myocardial infarction with normal coronary arteries in Chagas' Disease may include: embolic event's, particularly when there is associated congestive heart failure; coronary thrombosis and coronary spasms.

Infectious agents in coronary atheromas: a possible role in the pathogenesis of plaque rupture and acute myocardial infarction

In this review we report our recent findings of histopathological features of plaque instability and the association with Mycoplasma pneumoniae (MP) and Chlamydia pneumoniae (CP) infection, studying thrombosed coronary artery segments (CAS) of patients who died due to acute myocardial infarction. Vulnerable plaques are known to be associated with fat atheromas and inflammation of the plaque. Here we demonstrated that vulnerability is also related with focal positive vessel remodeling that maintains relatively well preserved lumen even in the presence of large atheromatous plaques. This phenomena may explain why the cinecoronariography may not detect large and dangerous vulnerable plaques. Greater amount of these bacteria in vulnerable plaques is associated with adventitial inflammation and positive vessel remodeling: the mean numbers of lymphocytes were significantly higher in adventitia than in the plaque, good direct correlation was obtained between numbers of CD20 B cells and numbers of CP infected cells in adventitia, and between % area of MP-DNA in the plaque and cross sectional area of the vessel, suggesting a cause-effect relationship. Mycoplasma is a bacterium that needs cholesterol for proliferation and may increase virulence of other infectious agents. In conclusion, co-infection by Mycoplasma pneumoniae and Chlamydia pneumoniae may represent an important co-factor for plaque instability, leading to coronary plaque thrombosis and acute myocardial infarction, since larger amount of these bacteria strongly correlated with histological signs of more vulnerability of the plaque. The search of CMV and Helicobacter pilori in these tissues resulted negative.

Detection of the viable myocardium. A perfusion scintigraphic study, before and after coronary bypass surgery in myocardial infarction patients

OBJECTIVE: To compare single-photon-emission computed tomography (SPECT) imaging scans using 201Tl and 99mTc-MIBI in detection of viable myocardium, in regions compromised by infarction. METHODS: Thirty-two (59.3±9.8 years old and 87% male) myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of <50%. They underwent coronary and left ventricle angiographies and SPECT before (including 201Tl reinjection) and after coronary artery bypass surgery (CABG). Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. RESULTS: Among 102 studied regions of the heart, there were 40 (39.2%) areas of transient perfusion defects in the conventional protocol with 201Tl and 52 (51.0%) after reinjection. Therefore, 12/62 (19.4%) more viable regions were identified by reinjection. Using 99mTc-MIBI, only 14 (13.7%) regions with transient defects were identified, all of which were seen also in 201Tl protocols. After surgery, 49 of a total of 93 regions analyzed (52.7%) were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, 201Tl SPECT scans - 65.3%, 90.9%, 77.4%, 88.9% and 70.2%, reinjection protocol with 201Tl scans - 81.6%, 81.8%, 81.7%, 83.3% and 80.0%; 99mTc-MIBI SPECT scans - 20.4%, 90.9%, 53.8%, 71.4% and 50.6%. Logistic regression demonstrated that the reinjection protocol with 201Tl was the best predictor of viability (P<0.001). CONCLUSION: Our data suggest the election of 201Tl for viability studies, especially when using the reinjection protocol.

Essential thrombocythemia and acute myocardial infarction treated with rescue coronary angioplasty

A 48-year-old man with essential thrombocythemia suffered an extensive anterior acute myocardial infarction; this is a rare association. A pharmacological thrombolysis was performed, without success. He subsequently underwent successful rescue coronary angioplasty. To our knowledge, there is no other report in the literature relating the triad of essential thrombocythemia, acute myocardial infarction and rescue coronary angioplasty.

Primary coronary angioplasty and stent implantation in acute myocardial infarction. Comparative analysis of the in-hospital results in the CENIC/SBHCI registry

OBJECTIVE: Comparative analysis of the in-hospital results after primary implantation of stents or coronary balloon angioplasty in patients with acute myocardial infarction (MI). METHODS: CENIC (National Center of Cardiovascular Interventions) gathered data on 3,924 patients undergoing coronary angioplasty (in the primary form, without the previous use of thrombolytic agents) in the first 24 hours after a MI, during the period of 1996-1998. From these 3,924 patients, 1,337 (34%) underwent stent implantation. We analyzed the success of the procedure and the occurrence of adverse cardiac events. RESULTS: In patients undergoing stent implantation there were more males (77% vs 69%, p=0.001), previous by pass surgery (6.3% vs. 4.5%, p=0.01), anterior MI and stent implantation in left descending artery (55% vs. 48% vs. p=0.009), and saphenous vein bypass grafts (3.3% vs. 1.9%). the procedure was more succesful in the group of stents (97% vs. 84%, p=0.001) and reinfarction rate (2.5 vs. 4%, p=0.002). The need for emergency revascularization was similar (1% vs. 1.1%, NS). Total in-hospital mortality was lower in stent group (3.4% vs. 7. 2%, p=0.0001) and this effect was in patients Killip class III/V (19.5% vs. 32.5%, p= 0.002) because there was no difference in patients class I/II (1.7% vs. 2.8%, p=0.9). CONCLUSION: Primary stent implantation in acute myocardial infarction showed better early results than balloon angioplasty alome.

Acute myocardial infarction in the Brazilian State of São Paulo. In-hospital deaths from 1979 to 1996 and hospital fatality from 1984 to 1998 in the public health system

OBJECTIVE: To determine the following parameters in the Brazilian State of São Paulo: 1) the percentage of deaths due to acute myocardial infarction (AMI) occurring in hospitals; 2) the percentage of deaths due to AMI occurring in public health system hospitals as compared with all in-hospital deaths due to AMI between 1979 and 1996; 3) the fatality due to AMI in public health system hospitals from 1984 to 1998. METHODS: Data were available on the Datasus Web site (the health information agency of the Brazilian Department of Health) that provided the following: a) number of deaths resulting from AMI in hospitals; b) number of deaths resulting from AMI in public health system hospitals; c) number of hospital admissions due to AMI in public health system hospitals. RESULTS: The percentage of in-hospital deaths due to AMI increased from 54.9 in 1979 to 68.6 in 1996. The percentage contribution of the public health system to total number of deaths due to AMI occurring in hospitals decreased from 22.9 in 1984 to 13.7 in 1996; fatality due to AMI occurring in public health system hospitals had an irregular evolution from 1984 to 1992 and showed a slight trend for increased frequency from 1993 to 1998. CONCLUSION: The percentage of in-hospital deaths due to AMI has been increasing. Deaths resulting from AMI in public health system hospitals have decreased when compared with the total number of deaths due to AMI in all hospitals. Fatality due to AMI in public health system hospitals did not decrease from 1992 to 1998.

Mortality attributed to myocardial infarction in the male and female population of Salvador, BA, between 1981 and 1996

OBJECTIVE: To describe according to gender the trend in mortality attributed to myocardial infarction (MI) in the population of Salvador, Bahia between 1981 and 1996. METHODS: This study was on mortality due to MI estimates by period and gender of the city of Salvador, Bahia. Data from 1981 to 1996 were stratified by quadrienia, and the percentage reduction in death rate due to MI relative to the preceding period (PRR) was determined. Comparisons between genders were expressed by the male/female death ratio (DR) based on the gender-related PPR. RESULTS: An overall increase of approximately 8% was observed in the death rate attributed to MI for the period 1985-1988 (89.2/10 5 individuals / year) versus the period 1981-1984 (82.1/10(5)/ year). In the subsequent periods, overall reductions of 10% and 20.3% were observed for the periods 1989-1992 and 1993-1996, respectively. For men, the PPRs were 11.1 in the period 1989-1992 and 22.7% in the period 1993-1996. The PPRs in women were lower: 8.6% and 17.4% between 1989 and 1992, and 1993 and 1996, respectively. Death rate reduction was greater for men than women, then the male/female DR decreased from 1.66 in 1981-1984 to 1.35 in 1993-1996. CONCLUSION: The results indicate a trend towards a reduction in the death rate attributed to myocardial infarction in the city of Salvador from the second half of the 1980s onwards, striking in men.

Myocardial infarction and subsequent pregnancy

We report the case of a 40-year-old woman with 2 previous myocardial infarctions, revascularization surgery, and an ongoing pregnancy complicated with preeclampsia and fetal hypoxia. Her follow-up performed by a multidisciplinary team made possible the birth through cesarean section of a premature infant of the female sex with a very low birth weight, but without severe respiratory distress of the hyaline membrane disease type. Three months after the delivery, mother and daughter were healthy.

Clinical significance of in-hospital reocclusion after mechanical reperfusion and percutaneous transluminal coronary angioplasty for acute myocardial infarction

OBJECTIVE: To analyze the effects of in-hospital reocclusion of reperfused AMI culprit coronary arteries in mortality and to identify the predictors. METHODS: The present study comprises a sample of 155 patients with AMI who underwent successful mechanical reperfusion by direct coronary angioplasty and angiographic control during hospitalization or before discharge. Patients were classified into group A: reoccluded patients (n=30) and group B: non-reoccluded patients (n=125). RESULTS: We identified in-hospital reocclusion predictors and found a greater significance in mortality among reoccluded patients (23,3% x 1.6%; p=0.00004). Silent reocclusion or typical angina at reocclusion had a good prognosis. The independent predictors of in-hospital mortality were hypertension, multiarterial lesions, totally occluded AMI culprit lesions, failed redilatation, failed redilatation in comparison with no intention to redilate, no redilatation in comparison with no atempt to redilate, and reocclusion within the first 48 to 72 hours. The decision to redilate, independently of the result, led to a 50.0% reduction in hospital mortality (p=0.0366). CONCLUSION: In-hospital AMI culprit coronary artery reocclusion had an adverse effect similar to that reported in clinical studies with high mortality rates (23.3% x 1.6%; p=0.00004). The major contribution of this study is to recommend the reopening of reoccluded AMI culprit coronary arteries as a means for the management of coronary artery reocclusion.

A comparative analysis of primary stenting and optimal balloon coronary angioplasty in acute myocardial infarction. Six month results from the STENT PAMI trial

OBJECTIVE: To compare the outcome of balloon PTCA with final coronary stenosis diameter (SD) <=30%, with elective coronary stenting. METHODS: We performed a comparative analysis of the 6 month outcomes in patients treated with primary stenting and those who obtained an optimal balloon PTCA result treated during the first 12 hours of AMI onset included in the STENT PAMI randomized trial. RESULTS: The results were analysed into 3 groups: primary stenting (441 patients, SD=22±6%), optimal PTCA (245 patients), and nonoptimal PTCA (182 patients, SD= 37±5%). At the end of the 6 months primary stent group presented with the lowest restenosis(23 vs. 31 vs. 45%, p=0.001, respectively). Ischemia-driven target vessel revascularization rate (TVR) (7 vs. 15.5 vs. 19%, p=0.001, respectively). CONCLUSION: At the 6 month follow-up, primary stenting offered the lowest restenosis and ischemia-driven TVR rates. Compared to optimal balloon PTCA. Nonoptimal primary balloon PTCA pts (SD=31-50%), had the worst late angiographic outcomes and should be treated more actively with coronary stent implantation.

Pseudo-myocardial infarction during an episode of herpes zoster

The patient arrived at the emergency unit with a history of acute myocardial infarction, for which she was treated. Without improvement in the pain, the patient developed heart failure and underwent a hemodynamic study, which showed normal coronary arteries and extensive ventricular impairment. During evolution, the clinical findings improved and herpes zoster appeared on the right shoulder. In a few months the clinical findings subsided, and the findings of the electrocardiogram, chest X-ray, and ventricular function were normal. The patient is currently asymptomatic.